Today’s central air conditioners have gotten a lot quieter than units of just a few years ago. High-efficiency units incorporate sound-dampening technology and two-stage compressors to produce noise levels below 69 decibels. So if you hear unusual sounds coming from your air conditioner during normal operation, that could be a sign that something is amiss and the unit needs repair or upgrade. A/C noise can be divided into three categories according to the source: ductwork, indoor air handler or outdoor condenser unit. Here are some of the sounds you might hear from those components and what they might mean.

Duct noises

  • Air leaks in the return ducts suck air in and may cause hissing, whistling or roaring. Leaky connections between duct segments can make similar noise.
  • Blower and fan noises such as squeaks, squeals and rattles may be transmitted though the duct system to rooms elsewhere in the home.
  • Animals inhabiting ducts can create scratching, fluttering and buzzing sounds.

Air handler noises

  • Hissing sounds can result from air leaks. Bubbling and hissing may signify a refrigerant leak in the evaporator coil or the refrigerant line.
  • Ticking or clicking noise may be caused by the fan blades striking an obstruction sucked into the blower.
  • A continuous humming sound can come from a burned-out or seized blower motor. A loose blower fan pulley will make a rattling noise while squeaking can indicate dry blower fan bearings.

Outdoor condenser/compressor noises

  • Banging or clanking sounds from the compressor indicate a defective piston or other major internal failure.
  • Buzzing sounds from the condenser fan motor may be traced to a burned-out motor or fan relay switch.
  • Occasional clicking sounds may be relays such as the spring-loaded contactor in normal operation. If they are repetitive, they can indicate a faulty thermostat continuously sending on/off signals.
  • A high-pitched hissing or “screaming” sound from the compressor indicates a dangerous high-pressure condition. Turn off power to the unit immediately.

Comfort Systems serves Wichita area homeowners with heating, cooling and plumbing needs 24/7. Give us a call and let us solve the mystery of those unusual noises you’re hearing from your air conditioner.

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